Chronographs of this type are already known to those skilled in the art. One such chronograph is disclosed in WO Patent No. 2008/075147. This is a chronograph that includes a chronograph train, coupling means, reset means and a control device for the coupling means and reset means. The control device includes a pivotably mounted shuttle, a first angular sector of which is provided with three notches defining three stable angular positions, respectively corresponding to the “reset”, “start”, “stop” functions, and an elastic member cooperating with the notches to hold the shuttle in one of the positions. The control device further includes a push-piece provided with a hinged finger with two beaks, cooperating with a series of cut out or blanked portions formed in a second angular sector of the shuttle, so as to cause the shuttle to change, via successive applications of pressure, from the reset position to the start position, from the start position to the stop position, then from the stop position to the reset position, and so on. The complex shape of the cut out portions and the two beaks is designed so that, depending upon the initial angular position of the shuttle, a first beak causes pivoting in one direction or the other, while the second beak locks the pivoting movement at the end of travel. The two beaks alternately perform the push and lock functions when the user presses repeatedly on the push-piece. The entire, three phase operating cycle of the single push-piece chronograph thus described is completed in three applications of pressure.